Users are reporting that computers with older processors made by Advanced Micro Devices (AMD) on board will not start up after installing a package of fixes for Windows that includes mitigations for the Meltdown and Spectre chip flaws.
Users vented their frustration over attempting to recover their systems after the failed updates installed, often automatically.
And Microsoft and AMD are working on the issue, but the fact that an unknown number of PC owners with AMD CPUs are going to have to wait to have their devices protected from the unsafe bug is incredibly disappointing.
AMD said there was a "near zero risk" its chips could be exploited by the second Spectre attack, which required OEMs to issue firmware updates containing CPU fixes - such as Intel's IBRS microcode fix or Google's Retpoline software fix.
The company has blamed AMD's own documentation, which apparently does "not conform to the documentation previously provided to Microsoft".
AMD was not immediately available for further comment.
From the earliest rumors, the performance decrease from Meltdown and Spectre ranged from negligible (2% or less) to significant (20% or more), on both Linux servers and Windows machines.
Microsoft said on Tuesday it had suspended patches to guard against Meltdown and Spectre security threats for computers running AMD chipsets after complaints by AMD customers that the software updates froze their machines.
The effects on AMD-based PCs weren't mentioned by either Intel or Microsoft.
Preventing Meltdown and Spectre attacks involves a software update that changes how a specific processor feature is used.
For the full details on the block put on the update, check out this Microsoft support post.
There's no timeline yet for when the problem might get resolved and working updates for affected AMD systems released.
The problem was no doubt exacerbated by vendors rushing to ship even basic mitigations for the Meltdown and Spectre flaws (see Meltdown and Spectre: Patches and Workarounds Appear).
The development is a setback for AMD, which was more narrowly impacted by the bugs than its rival Intel was. As part of a coordinated vulnerability program, all involved researchers and notified organizations agreed to not publicly announce the flaw until January 9, at which point many planned to issue patches.
Microsoft has released a patch that will be delivered in your normal update cycle for your laptop. If true, then it would be obvious that Microsoft failed to consult with AMD on the matter prior to issuing the patch.